The present invention relates to a locating system and method and, in particular, to a locating system and method for determining the location of an article relative to a crop row.
It is common in the agricultural industry to plant food crops in rows, each row being spaced from an adjacent row by a predetermined distance and the rows being generally parallel to each other. The areas between the crop rows facilitate access to the crops for the purpose of tending the crops.
In order to reduce the presence of weeds both in such areas between the rows and amongst the crops, it has been common to spray the crops with herbicides. However, such use of herbicides on food crops is becoming of greater concern to the public as excessive use of herbicides and fertiliser cause contamination of produce and excessive levels of nutrients in waterways. The use of herbicides for this purpose also introduces additional expense into the growth of the crops.
A solution to the above mentioned problem is to employ a manually controlled mechanical weeding apparatus to remove weeds between the crop rows. However, in order to remove the weeds with such mechanical weeding apparatus, it is necessary to accurately steer the mechanical weeding apparatus between the crop rows so as to avoid damaging the crop. This is often extremely difficult as the crop rows are generally not perfectly straight. Manual movement of the weeding apparatus is also very slow.
An alternative method of guiding a mechanical weeding apparatus incorporates a vision based system using CCD imaging and computer analysis to determine the location of the apparatus relative to the crop rows. However, although such a system operates satisfactorily in determining the location of the crop rows, the system is complex and expensive, and the accuracy of the system is dependent on weed density, the shape of the crop and wind and lighting conditions.
In accordance with one aspect of the present invention, there is provided a locating system for determining the location of an article relative to a crop row, the system characterised by including a set of markers capable of being buried, the set of markers being substantially linearly disposed at spaced intervals substantially parallel to and along the length of the crop row, the set of markers having a predetermined characteristic selectable from a range of possible characteristics such that the predetermined characteristic is specific to the set and a sensor unit mounted relative to the article, in use, substantially above the markers, the sensor unit being arranged to detect a signal corresponding to the predetermined characteristic of the set of markers and to generate a sensor signal indicative of the location of the sensor unit relative to the set of markers and thereby of the article relative to the crop row.
In accordance with a further aspect of the present invention, there is provided a method of determining the location of an article relative to a crop row, the method including the steps of selecting a set of markers having a specific predetermined characteristic from a range of possible characteristics, the markers being capable of being buried, disposing the set of markers substantially linearly at spaced intervals substantially parallel to and along the length of the crop row, and providing a sensor unit mounted relative to the article, substantially above the set of markers, the sensor unit detecting a signal corresponding to the predetermined characteristic of the set of markers and generating sensor signal indicative of the location of the sensor unit relative to the set of markers and thereby of the article relative to the crop row.
The article may be a mechanical weeding apparatus and the weeding apparatus may include a movement actuator adapted to adjust the lateral position of the weeding apparatus relative to the crop rows in response to the control signal from the control means. In this way, the location of the weeding apparatus may be adjusted so that the weeding apparatus is maintained in the desired location relative to the crop row whereby weeds are removed without damaging the crop.
Alternatively, the article may be a herbicide spraying apparatus or fertiliser disposing apparatus which includes a movement actuator adapted to adjust the lateral position of the spraying apparatus or disposing apparatus relative to the crop rows in response to the control signal from the control means. In this way, the location of the spraying apparatus or disposing apparatus relative to the crop may be maintained, and herbicide may be sprayed only on weeds in areas between adjacent crop rows or fertiliser may be disposed only on crops.